Ever since learning about their existence, I have been looking to spot some anticrepuscular rays. Every sunset and sunrise I've seen in the last few years, I have looked to the opposite horizon, but not until this month have I witnessed the phenomenon first hand.
Anticrepuscular rays are visible sun rays that converge on the anti-solar point in the sky, the point exactly opposite the sun on the horizon. The fact that crepuscular rays appear to diverge and anticrepuscular rays appear to converge are merely tricks of perspective due to viewing them pass through our spherical atmosphere. It's a natural optical illusion.
Anticrepuscular rays, with foreground grass.
Without foreground grass. The full moon is proof that these are anticrepuscular rays and not crepuscular rays, because if the sun had just gone down in this direction, the moon could not be full. The sun must be behind the camera.
Anticrepuscular panorama. View a little larger.
Seeing anticrepuscular rays during our trip to Extremadura was a real delight. Remember this post next time you see a beautiful sunset and look to the opposite horizon. You might just get lucky.